94 bonneville SSE

[Dalek]

Hello

I'm having a heck of time figuring this one out.

About 2 months ago my son says his bonne is running really rough, it doesn't seem to have much for power, and smells hot. The temp is in the normal temp range, and no check engine lights.

The car has 200K + miles on it and we weren't sure when the plugs were changed last, so I changed the plugs and wires. It seemed to run a little better but not great. I then replaced the fuel filter think we still didn't know when that was changed.

so I take it on a 10 mile drive on a state highway thinking my sons trips to school and back may have not given the engine a good work out. As I'm nearing home I get the feeling that the car is running way hotter then it should but the temp gauge is reading in the normnal range. In fact, I start smelling like I'm getting smoked like a ham. I pull into the driveway and look under the car and the catalytic converter is glowing red.

Seeing that I figure hay it's the o2 sensor. I change that and It is still running like crude with a glowing cat.

Any thoughts anyone?
Head problem? I haven't done a compression test yet. Antig-freeze is holdin level.
timing issue? how does one test that on a car without a distributer?

Thanks for any help in advance
Have a great weekend.
Dale

[maxwedge]

An excessively rich or lean condition or an engine misfire can cause this condition, if no misfire and the performance seems ok, I would do a full scan and look at fuel trims and sensor inputs. No way to change the timing, no distr.

[sad-lumina-owner]

Its not burning too lean OR too rich, its definitely burning too RICH:

Makes A Converter Become Red Hot?
A A Converter will get red hot when raw fuel is introduced directly into it. This is not the problem of the converter itself, but the result of a problem with the fuel system or ignition that allows unburned fuel to pass through the engine to the converter. Possible causes are improper ignition timing, fouled spark plugs, and air pump failure.

Q What Causes A Converter To Become Clogged?

A If a converter is operated too long at a high temperature, its substrate may "melt down" and turn into a solid mass inside the converter. The vehicle may seem sluggish, as if there were a loss of power. Again, an engine and/or fuel system malfunction is allowing a rich fuel mixture to reach the converter. If the problem is not diagnosed and corrected, future converter failures may occur.

http://catalyticconverter.org/faq/index.htm


Why does my catalytic converter glow red hot??

It's NOT clogged (yet) and it's not "doing it's job." A cat normally gets very hot when in use, but NOT GLOWING hot.

Something is causing raw unburned fuel to be sent down the exhaust pipe where the cat "burns" this fuel. The cat is designed to burn the tiny amount of unburned fuel that comes from a normal engine. Now, if you pour excessive hydrocarbons (fuel) in the exhaust, the cat will burn that too and since it's burning too much fuel it glows red hot. This won't last very long, this is very damaging to the cat. The catalyst can get hot enough to melt. And that won't take long! And when it melts, then you will have a blob of molten metal blocking the exhaust pipe (now it's clogged!) and the engine will stop operating. At that point, the only fix is replacement of the catalytic converter.

However, if you find and fix the problem now you can avoid that expense. You have to find why raw fuel is going through the engine. The most common reason would be a bad spark plug or bad spark plug wire. If the spark doesn't work, there is no "combustion" in that cylinder and the raw unburned fuel goes out the exhaust pipe.

A spark plug can be replaced for 0.97 cents, but if you wait till the cat melts, well those can cost $100's or more to replace.

Other problems could be a bad carburetor mixture, bad computer causing overly rich mixture, clogged fuel injectors, even bad /burnt valves and/or rings but heck lets not think about that.

But get an expert to look at it NOW and don't drive it any more till it's fixed, or that cat will melt and then you'll be in deep do do.

http://answers.yahoo.com/question/in...9200831AA55Lc6

[Dalek]

sorry never posted the resolution to this problem.

It turned out that two of the coil packs had very weak spark.
He had the two packs replaced and it has been running great.